DESCRIPTION: (Applicant's Abstract) This proposal is for the University of Houston, College of Optometry (UHCO) to serve as one of four clinical centers in the Correction of Myopia Evaluation Trial (COMET). COMET is a prospective, randomized clinical trial designed to assess whether progressive addition lenses (PAL's) slow the progression of juvenile-onset myopia, compared to conventional single vision lenses (SV). A total of four hundred children, 6-12 years of age with myopia (-1.25 to -4.50 D) in both eyes, who meet specific inclusion and exclusion criteria will be enrolled in the 4 participating centers. One hundred twelve children will be identified in Houston. These children will be recruited primarily from the University Eye Institute (UEI - the Clinic at UHCO). All eligible children will be examined at baseline and at six-month intervals for at least three years to measure changes in refractive error and to update prescriptions. A standardized, common protocol will be used at all four centers. The primary outcome measure is progression of myopia, as measured by cycloplegic autorefraction. A additional outcome measure is axial elongation as measured by A-scan ultrasonography. These outcome measures will be obtained by masked examiners. This application documents the ability of UHCO to recruit at least 112 children within one academic year, and to retain them for at least three years. Documentation is also provided that UHCO has the personnel, equipment, and facilities to conduct the study in accordance with the COMET Manual of Procedures (MOP). Complete details of the COMET rationale, design, and methods are contained in the MOP, which is submitted separately with the Study Chair and Coordinating Center applications. In addition to UHCO, the other clinical centers are located at Colleges of Optometry in Boston, Birmingham, and Philadelphia, with the Study Chair in Boston and the Coordinating Center at Stony Brook NY.